Gun perforator



M A H K R A M L S GUN PERFORATOR Filed March 19, 1945 INVENTOR. 51.. H A R KHAN Aug. 3, 1948 GUN mamas-iron Selwyn L. Markham, Houston, Tex, assignor to Tommy Yett, Houston, Tex.

Application March 19, 1945,Serial No. 583,509

9 Claims. I

The invention relates to a gun perforator and particularly to a construction thereof whereby a substantial increase is provided in the volume of explosive material which can be incorporated for the purpose of discharging the perforating bullet.

Considerable difllculty has been encountered with gun perforators in obtaining the desired penetration by the bullet. It will be understood in a great many instances the penetration is to be made not only through the steel casing or pipe in the well bore but that very often such pipe is cemented into position by having cement pumped downwardly therethrough and upwardly through .the well bore around the outside of the casing. Such cement is for the purpose of anchoring the casing and cementing oil the various formations to prevent leakage along the outside of the casing from one area to another. In some instances this layer or liner of cement may have substantial thickness, depending on whether or not the casing is centered in the hole and whether or not the formation may have washed away somewhat to a larger diameter during the drilling operation.

It is well known that the softer formations are inclined to wash out somewhat so as to create a larger diameter opening at the elevation of such softer formations. When the cement is pumped into place, it of course fills this larger cavity and results in a ring or band of cement around the pipe which may be substantially thicker than the layer of cement around the pipe where the well bore has not washed out. When a perforation is attempted at an elevation where a thick wall of cement has thus occurred, it has been found that in many instances the bullet did not have sufficient power to penetrate such a thick wall of cement, the result being that the bullet either sticks in the casin or in the cement with either a disappointing or disastrous result.

volume of explosive material is not one to be easily solved. v

i It is therefore one of the objects of the invention to provide an enlarged firing chamber for gun perforators.

Another object of the invention is to provide a gun periorator having an enlarged firing chamber to accommodate a greater amount of explosive material while retaining sufllcient strength in the body of the perforator to resist the shock 01 firing.

Still another object of the invention is .to supply a substantially pear shaped firing and explosive carrying chamber for gun perforators.

Another object of the inventionis to provide a firing chamber for gun perforators which has a frustoconical sidewall construction.

Another object of the invention is to provide a firing chamber having a frusto-conical sidewall construction and a concave base so as to provide a maximum area for explosive material.

Still another object of the invention is to provide a tapered firing chamber with a cylindrical choke or neck portion connected to the gun-barrel.

Still another object of the invention is to provide a firing chamber for gun perforators which is of substantially larger size than the standard cylindrical firing chambers and which is adapted to receive explosive material in pellet form.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings, wherein:

Fig. 1 is a vertical sectional view of a un perforator made up of subs or sections and to which the invention has been applied.

Fig. 2 is a section taken on the line 2-2 0 Fig. 1.

Fig. 3 is a side elevation looking at one of the gun barrels and the seal thereof.

It is well understood that a gun perforator may be made up of a plurality of sections or subs such as 2 which may be threaded at 3 for connection to the pin member 4 of an adjacent section or sub. Each sub 2 may have one or more lateral recesses 5 therein arranged to receive a bushing or bullet barrel 6 therein anchored by a thread I.

As indicated in the objects of the invention, it is desirable to provide a. maximum of explosive material within the gun perforator so asto obtain a maximum firing power to cause the bullet 8 to penetrate not only the pipe or casing but cement or other material therearound. To accomplish this, the recess 5 has been formed with a flat inner end ID, the center of which has been hollowed out to form a concave base II. This base is connected with a passage [2 to the detonation passage it which extends to the center It of the box portion ll of the section 2.

The bullet bushing B is oil peculiar construction in that it has a frusto-conical sidewall 20 which tapers toward the inner end of the bushing and is axially aligned with the concave base portion il so as to form a substantially pear shaped firing chamber 2|. The chamber thus far described is best seen in the lowermost sub 25 in Fig. 1. The chamber is filled with an explosive material 23 which may be packed loose into position but is preferably provided in the form of a pellet which can be inserted into the base of the bushing 8 prior to its being screwed into position in the sub 2. The bullet 8 will preferably fit snugly in the bullet barrel 26 so that it will be held firmly in place. A gasket 21 is disposed beneath the bushing 8 so that it may be deformed by the force of the explosion and tend to seal the bushing in position and prevent leakage.

In order to seal the outer end of the gun barrel a supporting disc 30 is surmounted by a patch 3| of resilient material, both of which are inserted in recessed area in the outer end of the gun barrel, such construction being disclosed in the copending application for patent of James G. Smylie, Serial No. 534,405, filed May 6, 1944 for Gun peri'orator now Patent No. 2,418,486 dated April 8, 1947.

The arrangement in ,the section 2 of the gun perforator is slightly modified as compared with the firing chamber in the sub 25. Such difference resides in the provision of a cylindrical area 33 which tends to merge the frusto-conical wall 2| with the bullet barrel 28. This cylindrical area forms a choke which tends to direct the pressure oi the explosion directly against the base of the bullet 8.

The upper bullet and bushing of Fig. 1 in section' 2 illustrates a plate or plug 40 which is of a size slightly larger than the choke area 33 so that the pressure of the explosion will force such wedge or plug outwardly. In this manner a tremendous pressure is built up in the firing chamber by having such a plug I resist discharge from the chamber. Thus if the bullet 8 should be more or less loose, this plug would serve to build up the pressure in the firing chamber so that it would be released as a unit against the bullet.

The resilient sealing ring 42 at the joint 43 between adjacent subs is the same as described in the above mentioned application of Smylie.

With the construction above described, the invention will be seen as broadly relating to the firing chamber of a gun perforator and providing of a chamber having a maximum area for explosive material.

What is claimed is:

1. A gun periorator including a body, a firing chamber therein, a bullet barrel connected to said chamber and extending to the periphery of said body, means to ignite the charge in said chamber, said chamber having a concave base and a frusto-conical side surface merging into said barrel whereby the force of the exploding powder charge is directed into said barrel.

2. A gun perforator including a body, a firing chamber therein, a bullet barrel connected to said chamber and extending to the periphery of said body, means to ignite the charge in said chamher, said chamber having a concave base and a Irusto-conical side surface merging into said barrel whereby the force of the exploding powder charge is directed into said barrel, said side and base configuration substantially increasing the size of said chamber.

3. A gun perforator including a body, a firing chamber therein, a bullet barrel connected to said chamber and extending to the periphery of said body, means to ignite the charge in said chamber, said chamber having a concave base and a i'rusto-conical side surface merging into said barre whereby the force of the exploding powder charge is directed into said barrel, said side and base configuration substantially increasing the size of the chamber to accommodate a larger explosive charge than in a body of the same diameter provided with a cylindrical firing chamber.

4. A gun periorator including a body, a cylindrical recess extending diametrically into said body, a base in said recess having a concave portion therein, a bushing threaded into said recess, a frusto-conical bore in said bushing, said concave portion and frusto-conical bore formin an enlarged firing chamber.

5. In a gun perforator a firing chamber, said chamber being shaped to provide a maximum volume for the explosive charge and to direct the explosive force into the gun barrel comprising a frusto-conical side wall and a concave base.

6. In a gun perforator a firing chamber, said chamber being shaped to provide a maximum volume for the explosive charge and to direct the explosive force into the gun barrel comprising a frusto-conical side wall and a concave base, and also having a cylindrical choke portion joining said side wall.

7. A gun perforator comprising apipe sub, a detonation passage therethru, a lateral recess, a concave base portion therein and connected to said passage, a bullet bushingremovably positioned in said recess, a bullet barrel in said bushing, said barrel flaring on its inner end to provide an enlarged firing chamber in combination with said concave base portion.

8. A gun perforator comprising a pipe sub, a detonation passage therethru, a lateral recess, a concave base portion therein and connected to said passage, a bullet bushing removably positioned in said recess, a bullet barrel in said bushing, said barrel flaring on its inner end to provide an enlarged firing chamber in combination with said concave base portion, and means to seal said barrel at its outer end.

9. A gun perforator comprising a pipe sub, a detonation passage therethru, a lateral recess, a concave base portion therein and connected to said passage, a bullet bushing removably positioned in said recess, a bullet barrel in said bushing, said barrel flaring on its inner end to provide an enlarged firing chamber in combination with said concave base portion. means to seal said barrel atits outer end, and a gasket sealing said bushing at the base of said recess.

SELWYN L. MARKHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Late 2,250,056 Alexander July 22, 1941 2,266,342 Spencer Dec. 16, 1941 2,327,141 Spencer Aug. 17, 1943 

